Hydrogen process



April '21, 1953 H, C, REED ET AL 2,635,947

HYDROGEN PROCESS Filed July 2J 1948Il Patented Apr. 21, 1953 HYDROGENPROCESS Homer C. Reed, Glendale, and Clyde H. 0. Berg,

Long Beach, Calif., assignors to Union Oil Company of California, LosAngeles, Calif., a corporation of California Application July 2, 194s,serial No. 36,723

(o1. zza- 214) 17 Claims.

This invention relates to an improved process and apparatus for theproduction of hydrogen and in particular relates to an improvedmodication of the process for the generation of hydrogen by the reactionof iron or iron oxide with steam.

Hydrogen has heretofore been generated by the interaction of iron andsteam according to the principles of the Messerschmidt process (U. S.Patent No. 971,206) in which a bed of sponge iron is heated toincandescence and then contacted with a blast of steam. The followingreaction takes place: 1

Following this iii-st step the resulting iron oxide was then reduced bycontactingV the oxidized bed of iron with a reducing gas such asproducer gas. Heat was supplied to the process and the step repeated,more hydrogen being produced.

This process had a number of disadvantages, among them being therelatively low degree of conversion of iron to iron oxide during thehydrogen production step, the poor heat and gas flow distribution in thebed of solids during operation, the problems encountered wherein theiron had a tendency to sinter or agglomerate with the resultantformation with larger iron particles than desirable and a decrease inactive surface area of the metal, and others. Another difficulty wasencountered in the deposition of carbon and the formation of carbidesduring the iron oxide reduction with a producer gas. These impuritiessubsequently reacted with the steam at high temperatures to form carbonmonoxide as well as some hydro-carbons which contaminated the hydrogenproduct.

These difficulties and disadvantages have been substantially overcome bythe process and apparatus of the present invention as hereinafter morefully described. The diiiculties formerly encountered with regard toheat ow and iron conversion have been overcome by employing a fiuidizedbed of solids in Which a continuous contact of reacting gases with thefinely divided solids is effected. In the hydrogen generation step inwhich iron or ferrous oxide reacts with steam to form higher iron oxidesand hydrogen and in the reducing step inwhich the higher oxides of ironare converted to elemental iron or lower oxides, precise temperature`control iseffected and the desired reactions are substantially carriedout to the desired products. By` this means, the problems encountereddue to iron sintering" with resultant loss of reactant solid surfacearea and the formation of troublesome iron impurities such as thosedescribed above which contaminate the hydrogen product have beeneliminated. The process, when carried out in the apparatus of thisinvention, operates smoothly and efficiently with a maximum productionof high purity hydrogen as hereinafter more fully described.

A primary object of this invention is to provide an improved process forthe production of high purity hydrogen through the reaction of steamwith a metal or an oxide of `a metal above hydrogen in the electromotiveseries of metals forming an oxide capable of reduction with carbon.

A further object of this invention is to provide methods for effectingthe reaction of iron and steam at elevated temperatures by means ofwhich effective temperature control and elimi nation of undesirablecontaminants from the hydrogen product are permitted.

It is another object of this invention to provide an improved method forreducing higher oxides of iron formed in the reaction of steam withWater by means of which iron-carbon impurities are substantiallyeliminated.

A further object of this invention is to provide a combined process forthe utilization of low A. P. Lgravity hydrocarbon fractions and thegeneration of hydrogen from the reaction of steam with iron.

It is a further object of this invention to provide a process forhydrogen generation by reacting a lower oxide of a metal such as ferrousoxide with Water or steam forming the higher oxide and subsequentlyreducing the higher metal oxide such as FezOs with carbon to ferrousoxide.

`It is another object of this invention to provide an improvedcombination process for the continuous coking of low A. P. I. gravityhydrocarbon fractions in the presence of a carbon reducible metal oxidein a higher oxidation state, the subsequent treatment of the coke-ladenhigher oxide particles at an elevated temperature to remove coke andeffect a reduction of the higher oxide particles to a lower oxidationstate, and the employment of the reduced particles thus formed as areagent for the reaction with steam at elevated temperatures for theproduction of high purity hydrogen.

It is also an object of this invention to pro-r vide an improved processfor the reduction of metallic oxides such as higher iron oxides and thefraction is coked in the presence of reducible n metallic oxide in afluidized system and the resultant coke-laden metallic oxidesubsequently treated at high temperatures in a second fluidized systemfor the substantially complete reduction of the metallic oxide to anydesired lower oxidation state.

It is also an object of this invention to provide an apparatus adaptedto effecting the a-fore` mentioned obj ects.

Other objects and advantages of this invention will become apparent tothose skilled in the art as the description and illustration furtherproceeds.

Briefly, the present invention comprises in its preferred modificationheating a'hydrocarbon fraction in the presence of particles of a carbonreducible metallic oxide, passing the resultant mixture into a fluidizedcokin'g zone in which thermal pyrolysis of the hydrocarbons isV effectedforming coke-laden metallic oxide particles and a coker distillatecomprising decomposition prod-- uctsy of` the hydrocarbon,. subsequentlytreating. the coke-laden particles of metal oxide at an elevated.temperature in a fluidized reducingzone wherein the coke-laden metallicoxide isY conver-ted to a gas con-taining carbon. monoxide. or carbondioxide and the iinel-y dividedV particlescontaining theI metal inv alower oxidation state which may be the elemental metal or a loweroxide,` combining the reduced-solid particles thusformedf with steam.and reacting the two in a u-idizedfzonewherein. they higher oxidationprod uct of the metal is formed together with hydroe gen, separating thehydrogen thus formed from the oxidizedmetal andv recirculating theparticles of oxidized metal together with the hydrocarbon tothe uidizedcokingA stage previously named. In this manner, the changel in theoxidation state of acarbon reducible element above hydrogen in theelectr-@motive series of metals isemployed to eiT-ectthe decompositionofwater for hydrogen production This material is alsoemployed to effectthe thermal decomposition of a gaseous or liquid hydrocarbon fractionsuch as natural gas, naphthaa gas oils, kerosenes,4

include lead, tin, nickel, cobalt, cadmium, iron,

chromium,v zinc, manganese, aluminum, beryllium', magnesium,.calcium,barium, strontium,. sodium, potassium, rubidium. and lithium. Of thisgroup-of metalsit ispreferable. to employ particles of metalliczinc,.manganese, iron, cobalt, nickel, or mixtures" thereofA orV loweroxidesY thereof since these metals. andoxides according to the process,

of this invention have suitable reaction rates with water or steam andat the' same time form oxidation products which are readily reduciblewith carbon according to the methods employed in this invention. Itis'pr'eferred to employ iron or ferrous' oxide in the" reaction of steamfor hydrogen production: and) the formation of a higher oxide of iron,either Fest); or FezOa or mixturesl thereof', and' it has been foundthat this oxidation product is readily reconverted to the`V elementaliron or ferrous oxidek according to the l" are oxidized in oxidizingregenerator In? the reducing regenerator', iron oxides formed in the'conversion of the iron suldesf andE process of this invention for reuse.The above statements regarding the preferred metals or compounds forhydrogen generation are not intended to restrict this invention to usewith that particular metal or its compounds since the process has beenfound readily operable with metals or oxidizable compounds of metalslistld inthe broader description above.

It is preferred to employ ferrous oxide (FeO) as the lower metallicoxide to decompose water in the hydrogen generation step of thisprocess. It has been found that in elevated temperature treatmentsyferrous oxide exhibits no tendency to agglomerata. sinter, or otherwiseloose its active surface area. In the following description of theprocess of this invention, ferrous oxide is used with water vapor togenerate hydrogen.

The processor the present invention may be morev readily understood byreference to the accompanying schematic` flow diagram which will bedescribedY in the. form. of anf example reciting flow quantities,temperatures, pressures, as well-v tion is presented employing coker le,reducingA regenerator lll, hydrogen generator l2 and oxi-A dizingregenerator I3. During the culling a cer.- tain amount of sulfides ofiron are formed which i3 to FezOs.

inf the reaction of lower oxides of iron or'elemental iron withV waterin hydrogen generator l2 are reduced at an' elevated temperature' toVfornr elemental iron or a lower iron oxide such as ferrous oxide` inthis modification'l The" l'ow' A. P. I. gravity hydrocarbon treatedvaccording tothe processv of' this-'invention is inv this' example atopped residuum obtained from aA Santa Maria Valley (California) crudeoil having a gravi-ty' of approximately 15 A, P. I.

This hydrocarbon is introduced.' by means of line Hl; and is pumped bymeans of pumpv f5 through line lid at a rate of 350 barrelsy (42 U'. S.gallons per barrel? per day andi is combined' with 150 tonsper day ofcoke-free iron oxide of which' low" as about 5 to as high as about 50theY ratio under preferred operating conditionsy is between about 25landi 4.5, these 'conditions including the quantity of circulated' solidsfrom the coker when cokirig inthe presencev of udized particles isemployed. The weight ratio of c'oke-free'iron oxide to coking stock isusually between 1:0 andi()` in fluidized coking operations. The ironoxide laden hydrocarbon streampa'sses via line 22 intocoker HI.

HYDROCARBON OIL COKING In one modification of the coking step of theprocess according to thisinvention the temperatureof the-hydrocarbonstream and of the higher ironV ox-ide stream isY sufficient to effect asubstantially complete, thermal pyrolysis of the hv-l drocarbon whilethe hydrocarbon is conveyed via line 22 into coker I0. In the presentoperation, for example, the higher iron oxides at about 1600 F. arecombined with the incoming hydrocarbon stream at temperatures of about750 F., in such a proportion that a hydrocarbon stream is raised totemperatures between about 700 F. and 1200* F. sufficient for thermaldecomposition as hereinafter described. Under these conditions coker I0may comprise a suitable separator such as the cyclone type in which thelower boiling hydrocarbon products of the thermal pyrolysis are removedvia line 23 controlled by valve 24 at a rate of about 300 barrels perday. This comprises the coker distillate which is subsequently conveyedby means of line 25 to fractionation facilities or storage or otheruses, not shown. The coke-laden particlesV of iron oxide which may beFesO'i or FezOs or mixtures thereof, are removed from the lower end ofcoker I0 and pass via line 26 into reducing regenerator H.

In another modification of the coking operation, coker I0 may comprise afludized vessel in which suitable circulation of gases or vaporsmaintain the coke-laden particles of the higher iron oxide and theentering particles of iron oxide in a state of hindered settling bymeans of which a dense phase suspension of these particles inhydrocarbon gases and vapors is maintained. A level is established belowwhich a suspension phase exists having a bulk density which isappreciably greater than the density of the vaporized hydrocarbons dueto the suspended solids present and 'in which the solids are coated withcoke. In this modification the operation is such that a continuouscountercurrent contact of suspended iron oxide particles with thehydrocarbon stream is effected at coking temperatures and a highlyefficient coating of veach particle with coke results. By withdrawing aportion of the fluidized phase and recirculating this material togetherwith incoming oil and solids in the abovementioned ratio through a heatexchange mechanism to supply heat, a precise control of the cokingtemperature may be effected.

Either of the aforementioned cokng steps may be employed.

From coker I Il coker distillate vapors are withdrawn and sent tostorage or further processing facilities, not shown, and coke-ladenparticles of iron oxide pass downwardly through line 26 into reducingregenerator II. In order to effect a substantially complete stripping ofthe coke'- laden solids, a stripping gas is introduced via line 2'!controlled by valve 28 into line 26. This stripping gas may comprisesteam, natural gas, producer gas or similar materials which passupwardly through line 26 and effect a countercurrent stripping ofresidual hydrocarbons present. The material ultimately discharged fromline 26 into reducing regenerator II comprises a dense phase ofcoke-laden particles of iron oxide. This stream in the present operationamounts to 160 tons per day and comprises 6.3% coke.

REDUCING REGENERATION The coke-laden oxides of iron are introduced in acontinuous stream into reducing regenerator II which is operated at atemperature of about 1200 F. and at a pressure of 30 pounds per squareinch. This operation may be conducted at pressures considerablyhigherthan the one cited, but preferably at no pressure less than this forreasons of control. Suitable temperatures for operating reducingregenerator II range from as low as 1,000 F. to as high as 1500 F. orhigher. Reducing regenerator II is a vessel. containing uidized solidsin which the coke-laden iron oxide particles are maintained in a stateof hindered settling by means of which suspension level 29 isestablished and maintained. A portion of the suspended solids areremoved from reducing regenerator II by means of line 3|] controlled byvalve 3l. These are suspended in a portion of the producer gas formed inreducing generator I I and returned through heat exchange means 32 vialine 33. This circulation maintains the uidized suspension of solids inthe reducing gases and permits precise temperature control and controlof the composition of solids ultimately produced from thereducing-regenerator. A. controlled amount of an oxygen-containing gassuch as air may be introduced into this recycle stream via line 39a.controlled by valve 40a, or it may be directly injected into vessel II.This gas is required to aid in oxidizing the coke to carbon monoxide.

The gaseous products of the reaction collect in astate relatively freeof suspended solids above level 29 in reducing regenerator I I Thesegases in the preferred operation according to this invention comprisemainly a mixture of carbon monoxide, hydrogen, carbon dioxide, water andnitrogen. The preferred form of operation is such that a carbon monoxideto carbon dioxide ratio of at least 1.0 is maintained to insure asubstantially complete reduction of the higher iron oxides to ferrousoxide (FeO). In other modications of this invention, increasing carbonmonoxide to carbon dioxide ratio to as high as about 3.0 or higherinsures the reduction of the higher oxides of iron substantiallycompletely to elemental iron which may be employed subsequently inhydrogen generator` I2 for the reduction of water vapor.

`Positioned in the upper portion of reducing regenerator II is separator34 into which the gases referred to above are introduced and by means of`which remaining traces of suspended solids are removed. The gases arewithdrawn therefromby means of line 35 and a portion is recirculatedthrough the regenerator at a rate of 1440 M s. c. f. per day via line 3Eby means of blower 31 controlled by valve 38 which in turn may beactuated by flow controller 39. This gas flows by means of line 40 andis combined with `the solids removed from reducing regenerator II bymeans of line 30 described above and is recirculated into the iiuidizedvessel. This recirculation of carbon monoxide-bearing gas in which thecarbon monoxide to carbon dioxide ratio has a specific value is ofconsiderable importance of successful operation of the reducingregenerator. By controlling the rate of this gaseous recycle, the degreeof contact of cokeladen iron oxide particles may be varied and bycarefullyk controlling the carbon monoxide concentration with respect tothe carbon dioxide concentration the composition of the reduced ironcompounds removed from the regenerator may be controlled. Excessquantities of this carbon lmonoxide containing gas are removed fromseparator 34 by means of lines `55 and 4I controlled by valve 42. Thismaterial comprises a producer gas which may be sent to storage orfurther proc-- essing facilities not shown, or in the preferredmodification of this invention is employed as fuel in the process.

At the temperatures of operation employed in lreducing regenerator lil.a substantially .conip'lete reduction .zo'fkthe higher oxides .of iron`is obtained in which .the .carbon ,present on .the individual ironoxide particles .apparently reacts `directly .to form carbon .monoxideand a lower oxide'of iron. 'Thecountercurrent contact'offered .to theresulting lower oxide of iron, which in .this lmodiiication comprisesyferrous oxide, Iby -the recirculated gas stream describedabove, inwhich .a specic concentration ratioof carbonimonoxide to .carbon dioxideis maintained, insures `a substantially complete reduction of the iron:oxides to ithe desired lower oxide or to the elementaliron state.

In this .modification the vferrous oxide is removed from .reducingregenerator l l by means of yline 43 controlled by valve llll at a rateAof 204 .tons .per day. This material has 4the Vfollowing analysis:

Table Weight .Component z `per .cent FeO '716.2 Fe304 '20.3 FeS v3.4 C0.1

`The ferrous oxide produced yas above ydescribed and having theforegoing composition passes via vline 45 and is combined vwith steam orwater `introduced by means -of line 4t controlled by valve 41 at a rateof about 26,000 pounds per day. Since the iron oxide removed fromregenerator kIl vialine 43 is at a temperature of about 1200 F.,efficient utilization of its sensible heat may be obtained by combiningit directly With liquid water under a pressure of about 30 pounds persquare inch` The steam thus formed is sufficient to ysuspend the ferrousoxide by means of which it is introduced via line 48 through heatexchange means 49 whereby temperature control of recirculated solids ismaintained, and subsequently through line 50 into hydrogen generator i2.heat of the ferrous oxide stream removed from reducing regenerator Il inother services such as pre-heating the recirculating carbon monoxidestream and the like. n this instance the heat may be recovered in asuitable waste heat boiler to cool the solids. Steam may then beintroduced via line 46 controlled by valve 4l to suspend the cooledferrous oxide particles directly.

HYDROGEN GENERATION Hydrogen generator I2 is operated with Va net upflowof gases introduced via line 50 which-comprise steam containingsuspended ferrous oxide together with some iron sulfide. In this mannerthe solid particles are fluidized and maintained in a condition ofhindered settling which establishes level 5I` below which the densephase,

Iwherein the reaction occurs, exists. A continuous countercurrentcontact of ferrous oxide and iron sulfide with steam is effected atatemperature of about 1200 F. although temperatures below about 800 F. to900 F. to higher than 1500 F. may be employed. The pressure of operationin this modification is about 30 pounds per square inch, although higherpressures may be employed, if desired.

Below level I in hydrogen generator I2 the following reaction betweensteam and ferrous oxide occurs:

It may be desirable to employ the sensible Y At these operatingtemperatures, a complex -reaction also takes place between .the steamand the iron .-sulde particles during which further quantities of.hydrogen are formed together with small amounts of hydrogen sulfide andconsiderable `quantities of sulfur. About 30% to 40% of the sulfurpresent as iron sulfide introduced into the hydrogen generator isconverted to elemental sulfur and removed with the .gaseous product.Some of Vthe solids remaining apparently are at least partiallyconverted to a solid compound or compounds of iron, sulfur andoxygen.`The :nature of the material thus formed has not been accuratelydetermined, but it is believed to be an iron sulte or an ironthiosulfate or a combination of `these or like materials. These complex,solid'compounds are readily oxidzable in :the oxidizing regenerator inwhich iron suldes are `converted to higher iron oxides forming sulfurdioxide.

The hydrogen `thus formed together with unreacted water vapor and sulfurvapor accomulates in the upper portion of hydrogen generator ;|2 abovelevel 5l and is passed through separator :52 Iwherein remaining tracesof suspended solid particles are removed and returned to the lower partof t-he vessel below level 5l. The hydrogen product is removed fromseparator 52 via line V53 at a yrate controlled by valve 54 which servesto maintain operating pressure in Ahydrogen generator l2. The Vhot gasesthus formed comprise a mixture of hydrogen, sulfur and steam a-t atemperature-of about 1200 F. and pass at a rate of 26 M s. c. f. perhour into heat exchange means which may comprise a steam superheaterserving to raise the temperature of steam introduced -into thegenerator. Ultimately the temperature vof `these gases is decreasedsufciently to permit condensation of the sulfur formed las aboveindicated separately from the water. The entire gas mixture may becooled to effect condensation of both the sulfur and the uli-reactedwater lvapor and the cooled mixture .passes by -means of line 56 intoseparator 5l. Hydrogen, lsubstantially free of water vapor, is removedtherefrom `by means of line 58 at a rate controlled by yvalve .59 Whileunreacted water containing condensedV sulfur lparticles as a condensatepasses via line 4controlled by valve 5l which in turn is actuated byliquid level ccn- .troller 6.2. Thesulfur may be readily separated bysedimentation, `ltration -or other well known means ,and the water maybe returned for revaporization to supply steam requirements. Thehydrogen thus Iproduced on the water-free bases .amounts to 11.5 M s. c.f. per hour and a 44% steam decomposition is effected under theseparticular operating conditions.

yHydrogen generator l2 is provided with means for withdrawing the higheriron oxides as well as complex iron sulfur oxygen compounds ,formed asproducts of the reaction of water vapor with ferrous oxide and ironsulnde. These outlets are further provided with steam seals by means ofwhich the solid particles may be withdrawn continuously without the lossof hydrogen from hydrogen generator l2 or the introduction of undesiredgases. Steam is introduced into outlet 60 by means of line Si controlledby valve 62. The solids are vthus removed via line IS at a temperatureof between about 1000 F. and 1600o F., controlled by valve -l 9 to becombined with incoming .-low A. P. II. gravity hydrocarbon fractionyto-be looked. The mixture is `.subsequently introyducedinto .Coker IDas previously described. The

'asseoir remaining portion ofhigher oxide of iron produced in hydrogengenerator I2 is removed via line 63.

The main body of the higher oxides of iron thus removed passes by meansof line 64 controlled by valve 65 and is combined with the lower oxidesof iron and steam introduced by means of line 48. The combined streampasses by means of line 86 and is recirculated into hydrogen generatorI2. The circulation of gases containing these suspended solids serves tomaintain level 5I in the hydrogen generator, the efcient countercurrentcontact of fluidized solids and gases and the precise temperaturecontrol over the hydrogen generation reaction.

The greater portion of higher oxides of iron removed from hydrogengenerator I2 pass through outlet 63 into which passes the steam as asealing gas by means of line 61 controlled by valve 68. As abovedisclosed, most of the material thus Withdrawn is recirculated to thehydrogen generator while the remaining portion passes via line 69,controlled by valve 10, at a rate of 110 tons per day and is introducedby means of line 1I into burner 12. A fuel gas, which may comprise partof a producer gas produced from reducing regenerator II or it maycomprise a hydrccarbongas, is introduced into burner 12 by means of line13 .at a ratecontrolled by valve 14 in turn actuated by flow controller`15. Air is supplied to the burner by means of line 16 and Ablower 11controlled by valve 18.

`The heat liberated in combustion raises the temperature of the higheroxides of iron from about 1200 F. to about 1600a F. The higher oxides ofiron are suspended inthe hot flue gases thus formed and pass via line 19upwardly into separator 80 wherein the solids are separated from the nuegas. The flue gas is removed therefrom via line 8l controlled by valve82 'and the precipitated "solids -pass by means of line 83 into reducingregenerator II where they are admitted below level 29 into the fluidizedphase present in that vessel, The higher oxides of iron are thusreturned to the reducing regenerator at a rate of 160 tons per `day andserve to supply heat required in the reducing regenerator.

`oxLLDIzitNGr REGENERATION When the process of this invention is carriedout using a low A, P. I. gravity hydrocarbon fraction containinghydrocarbon compounds of suly 'fur and. oxygen from building up in thesystem.

The oxidizing regenerator oxidizes these cornpounds of iron under hightemperature conditions to form gases containing sulfur or sulfurPdioxide and leaves higher iron oxides, mostly In order to effect ironsulfide conversion, 41 tons per day of solid material Withdrawn fromhydrogen generator I2 by means of lines 63 and VVlill is passed via line84 controlled by valve 85 and is subsequently combined with 38 M s. c.f. per hour of air under pressure from blower 11 inline 86 at a ratecontrolled by valve 81. The suspension of iron sulfide, iron sulte andiron l`oxide in air passes via line 81 wherein it is com- 10 lbined witha recycl streamA oiiron oxide withdrawn from oxidizing regenerator I3.The combined streams are subsequently passed by means of line 89 as asuspension through heat transfer means 90 and are introduced by means ofline 9|A into oxidizing regeneratior I3. The operation of oxidizingregenerator I3 is that of a fluidized process in which level 92 ismaintained wherein a continuous countercurrent contact of iron sulfidewith air is effected. The temperature of this operation is about 1200oF. and 2,300 M. B. t. u.. per'hour of heat is liberated, althoughtemperatures of from about 1000" F. to about2000 F. may be employed.This heat is dissipated in heat exchange means 981 which may be employedto generate high pressure steam forusein the remainder of the process orit may be employed 'to preheat incoming streams or recycle streamsemployed within the process. Below level 92in oxidizing regenerator I3the suspended particles of iron oxide and iron sulfides are maintainedin a condition of hindered settling and a substantiallycompleteoxidation ofthe iron sulfides and other solids is effected..` Theresulting gases collect in the portionv of the vessel above level 92 andare passed through separator 93.Wl1ich serves to separate the remainingsuspended solids and return them to a position below level 92.` Thesolids-free sulfur dioxide-bearing flue gases are then passed via line94 controlled by valve 95 and are disposed of or .sent to further`processing facili- -ties not shown.` In one modification of thisprocess, not shown in the drawing, carbon monoxide produced fromreducing regenerator II may. be combined with the nue gas produced fromoxidizing regenerator I3 in the proper proportion and reacted to convertthe sulfur dioxide t-o velemental sulfur which may be recovered as aliquid or as a finely ldivided solid. Iron sulde and lower iron :oxidesare converted in oxidizing regenerator.` I3 `to FezOa. which is removedtherefrom at a rate of 41.5 tons per day `via line 96. These `solidspass by means of line 96 into vessel 91 which is provided with baffleplatesior other` means whereby a countereurrent contact of a downwardlyflowing solid with an upwardly iiowing gas may be effected. Vessel 91'comprises an auxiliary reducer wherein -ferrie oxide FezOa is reduced toFesO4 by the action `of a gas containing a substantial proportion ofcarbon monoxide which is introduced by means of line 98 controlled byvalve 99. This gas may comprise a portion of the carb-on monoxidebearing gas produced in reducing regenerator `II or it may comprise aproducer gas separately prepared. This gas is introduced into auxiliaryreducer 91 aft a rate of 12 M s. c. f./hr. and the efliuent gases areremoved therefrom by means of line |00.

The reduced solids from auxiliary reducer 91 are withdrawn therefrom ata rate of 460 tons per day via line IUI controlled by valve I02. Themajor proportion of this, 420 tons per day, passes by means of line |83controlled by valve I94 and is recirculated through lines 89 and 9| tooxidizing regenerator I3 as previously described. The remainingproportion of the partially reduced solids pass by means of line 20Vcontrolled by valve ZI at a rate of 40 tons per day and is combinedwith the incoming low A. P. I. gravity hydrocarbon to be ooked.

1n this manner, a process for the active de- 'sulfurization ofhydrocarbon fractions combined with a process for the production oflarge: quan- IIv -tities of substantially; pure hydrogen results. VIfdesired, the hydrogen thus produced: may be employed in hydrogenatingthe relatively un- -saturated hydrocarbons present in.- thecokerdistillate. Preferably, this is carried out in a separate process eitherat high pressures and temperatures in the absence of a hydrogenationcatalyst or `at more moderate conditions of temperature and pressures inthe presencey of an active hydrogenation catalyst.

Although the foregoing description. has been limited to the generationof hydrogen by the re'- action of ferrous oxide (FeO) andA steam. and

lthe coking of a low A. P. I. gravity sulfur-containing crude petroleum,it. should be understood that these specific details; are not to' beconsidered as limiting the process of this invention to the specificconditions given since other hydrocarbon fractions such as thosepreviously given may' be employed. The con ditions of operationsdescribed above, particularly the temperature conditions. of thereducing regenerator, may be altered by increasing the temperature ofreduction and the ratio. of carbon monoxidey to carbon` dioxide. in therecycle gas to a value of about 3.0101 tor contain above about 75%,carbon monoxide wherebyl the solids removed from the reducing;regenerator contain appreciable quantities of elemental iron. The ironthus obtained is employed in substantially the same fashion as is: theferrousoxide (FeO) of the foregoing descriptionl by reacting it at anelevated temperature as. a fiuidized sus'- pension with Water vapor forhydrogen produc:- tion. When employing elemental iron in` this operationlsomewhat lower operating: temperatures may be employed and the recyclerates necessary for a given hydrogen! production. may

be decreased since the greater quantity of water is decomposed in.oxidizing elementalv iron: to FeaOi than that obtained when ferrous;oxide (FeO) is oxidizedv to F6304.

The pressures involved in theV process of this invention are moderate,vthat. is, between'` atmosfpheric and about 250 pounds per square inch.

-The fluidized. coker, reducing and oxidizing` refgenerators and.' thehydrogeny generator may be eiiiciently operated at pressures. of:between 1'5 and 100 pounds per square inch gauge. It isptobe understood,however, that these temperaturesl are typical of the operation describedand. are not intended to limit the scope. of the invention.

Oxygen-containing gaseszemployed.inztheprocess may be air or fluegases,.crA other gases. containing free oxygen are also desirable sincein the reducing regenerator inparti'cular lowerl Oxy.'- genconcentrations are desirable and must. be carefully controlled.

It should also be understoodthat` the'process of this invention is notlimited to the specific use of iron compounds in the reduction of watervapor for the production of hydrogen sinceother metals of atomic number25 through 30 except copper, such as nickel, cobalt, manganese and. thelike, as well as mixtures and alloys of these metals and compounds ofthese metals such as their oxides may likewise be employedaccording. tothe principles of operation cutlinedabove.

The use of Zinc and zinc oxide in particular have been found to besuitable inV hydrogenproduction according to this invention undersubstantially the same, conditions` given above for iron. Cobalt, nickeland manganese and their oxides may be employed also with littlevariationof the operation.

A particular'e'mbodiment cf the presentV invern',- tion has beenhereinabove described in considerable detail by Way of illustration. Itshould: be understood that various other modifications and adaptationsthereof may be made by those skilled in this particular art withoutdeparting fiomthe spirit and scope of this invention as set forth in theappended claims.

We claim:

l. A process which comprises coking a hydrocarbon oil in the presence offluidized particlesof a.' higher. oxide of irony at av temperature.between about 700 F. and about 120i)o E. formingacoker distillate andcoke-laden higher iront oxide" particles, separating said. Cokerdistillate. from. said particles, subjecting said coke-laden. particlesto treatment at a temperature between about 1000 F. and about 150i)c F.while in a iiuidized state in` a gas containing oxygen to effect. thecombustionof said coke therefrom and the direct heating and the carbonreduction of said. higher ironr oxide forming gases containing carbon'monoxide and coke-free reduced iron-containing particles, fluidizingthe' particles thus obtained. in steam at a temperature between about890 F. and about 1500 F. to form hydrogenand` thereby reforming thehigher iron oxide, separating.: hy'- drogen thus produced andrecirculating.I the higher iron oxide 13o-contact further quantities ofsaid hydrocarbon oil.

21 A process which comprises coking a hydrocarbon oil in the presence offluidized particles of ferrie oxide to form coke-laden ferrie oxideparticles and a coker distillate, separatingsaid coke'- laden particlesfrom said coker distillate; fluidiz'- ing said coke-laden particles in agas containing oxygen at' an elevated temperature to effect theoxidation of said coke and the direct heating and carbon reduction ofsaid particles of ferric oxide to form a gaseous mixture containingcarbon monoxide and coke-free particles of ferrous oxide, maintaining acirculation of at least part of said carbon monoxide as a recycle gascontaining a carbon monoxide to carbon dioxide` molar ratio of at least1.0 to fiuidize said coke-laden ferrie oxide particles, separating. saidferrous oxide particles from said carbon monoxide gases, fluidizing theVferrous oxide particles inv gas containing steam at an elevatedtemperature thereby reforming particles of ferrie oxide while liberatinghydrogen, separating hydrogen thus formed' from particles of ferricoxidev and recirculating the ferrie oxide to contact further quantitiesof said hydrocarbon oil.

3. A process which comprises coking a hydrocarbon oil in the presence offluidized particles of ferrie oxide to form coke-laden ferrie oxideparticles and a coker distillate, separating said coke.- laden particlesfrom said coke-laden distillate, uidizing said coke-laden particles in-agas containing oxygen at an elevated temperature sui'- cient to effectthe oxidation of said coke and the direct heating and carbon reductionof said particles of ferric oxide to form particles of elemental ironand a gaseous mixture containing carbon monoxide, separating saidelementaliron particles from-said carbon monoxide gases, maintaining acirculation of said carbon monoxide gases as a recycle gas having acarbon monoxide to carbon dioxide ratio of at least 3.0. toluidizesaidcoke-laden ferrie oxide particles to.- reduce uniformly said ferrieoxide particles to elemental iron particles, subsequently luidizing theyelemental iron particles in gas containing. steam at an elevatedtemperature thereby reforming particles of ferrie oxide While liberatinghydrogen, separating hydrogen thus formed from particles of ferric oxideand recirculating the ferric oxide to contact further quantities of saidhydrocarbon oil.

4. A process which comprises coking a hydrocarbon oil contaminated withhydrocarbon compounds of sulfur in the presence of fluidized particlesof FesOi at a temperature between about '700 F. and about 1200 F. toformlcoke-laden particles of FeaOi, iron sulfide and a coker distillateseparating the coker distillate thus formed from the aforementionedcoke-laden particles, contacting said particles with a stripping gas toremove traces of said coker distillate, fluidizing said coke-ladenparticles at a temperature between about 1000 F. and about 1500 F. in arecycle gas containing a controlled quantity of carbon monoxidesufficient to permit the oxidation of said coke and the direct heatingand reduction of said FesOi to coke-free ferrous oxide and formingcarbon monoxide from part of said coke in the presence of a gascontainingoxygen, employing at least part of the gas thus formed as saidrecycle gas, separating the carbon monoxide thus formed, suspendingcarbon free particles of ferrous oxide and iron sulfide in a gascontaining steam at a temperature between about 800 F. and about 1500 F.thereby decomposing at least a portion of said steam to liberatehydrogen and reform said particles of Feaoi, separating the hydrogenthus formed from said particles, suspending said iron sulfide in a gascontaining oxygen at a temperature `between about 1000" F. and about2000 F. thereby oxidizing said particles of iron sulfide forming a gascontaining sulfur dioxide and combining the oxidized particles with saidhydrocarbon oil to be coked.

, 5. A process which comprises combining a low A. P. I. gravityhydrocarbon oil contaminated by hydrocarbon compounds of sulfur withheated particles of Fe3O-4 in weight ratios of from 1.0 to 10.0 tons ofcoke-free solids `per ton of oil to effect a substantial degree ofcoking of said hydrocarbon oil to form a coker distillate and coke-ladenparticles of Fea04 and ferrous sulfide, separating the coker distillateAthus formed from said coke-laden particles, fiuidizing said cokeladenparticles at an elevated temperature in a gas containing oxygen and acontrolled quantity of carbon monoxide sufncient to permit thecombustion of said coke and the direct heating and reduction of saidparticles of FeaOi to form cokefree. particles of FeO and ferroussulfide, combining the coke-free particles thus formed with a gascontaining steam to form a fluidized suspension of said particles,maintaining the suspension at an elevated temperature thereby effectinga reaction beteen said FeO and said steam thereby liberating hydrogenand reforming particles of FesOi, separating said hydrogen from saidparticles of FesOi, recirculating a portion of particles of Fes04 andferrous sulfide to be combined with said low A. P. I. gravityhydrocarbon oil, suspending the remaining portion of particles of Fe3O4and ferrous sulfide in a gas containing oxygen to form a fluidizedsystem, heating said mixture to oxidize said ferrous sulfide and FesOirat an elevated temperature to FezOa forming a gas containing sulfurdioxide, contacting the particles of FezOs thus formed With a gascontaining carbon monoxide thereby effecting a substantial reduction ofparticles of FezOs to FesOi and recirculating the particles of Fes04 T14formed to contact further quantities of said drocarbon oil to be coked.

6. A processaccording to claim 5 wherein said coke-laden particles ofFeaOa and ferrous sulfide are reduced in a reducing regenerator zone toform coke-free particles of FeO and ferrous sulfide by fiuidizing saidparticles in a recycle gas produced in said reducing regenerator zoneand having acarbon monoxide to carbon dioxide ratio of at least 1.0 anda controlled quantity of oxygen and which is recirculated through saidreducing regenerator zone.

7. A process according to claim 5 `wherein heat is supplied to effectthe reduction of FeaOr to FeOl which comprises separating particles ofFeaO4 and ferrous sulfide from said hydrogen, suspending the particlesthus separated in flue gas at an elevated temperature thereby heatingsaid particles and combining the thus heated particles` of Fe304 andferrous sulfide with the cokeladen particles of Fe3O4 and ferroussulfide.

8. A process which comprises establishing a coking zone, a fluidizedreducing regeneration zone, a luidized hydrogen generation zone and afluidized oxidizing regeneration zone, maintaining a level of suspendedsolids in each of said fluidized zones, contacting a low A. P. I.gravity hydrocarbon oil contaminated with hydrocarbon compounds ofsulfur with heated particles of FeaOe and FeS in a ratio of from 5 to 50tons of solids per ton of `oil to` effect a substantial degree of cokingof said hydrocarbon oil to form cokeladen particles of Fea04 and Fes anda coker distillate within said coking zone, separating said cokerdistillate from said coking zone, passing coke-laden particles of FesO'iand Fes from said coking zone into said uidized reducing regenerationzone, introducing a gas containing oxygen into said reducingregeneration zone thereby maintaining an elevated temperature therein byoxidation of said coke and thedirect heating of said particles causingthe reduction of said FesO/i forming coke-free particles of FeO and Fesand a gas containing carbon monoxide, recirculating a portion of carbonmonoxide bearing gases thus formed through said fluidized reducingregeneration zone while controlling the ratio of carbon monoxide` tocarbon dioxide thereof, removing coke-freev particles of FeO and FeSfrom said reduring zone, combining said particles at an elevatedtemperature with a gas containing .steam in said uidized hydrogengeneration zone, reacting said FeO with said steam to form hydrogen andreforming said FesOi, separating the hydrogen thus produced, combining afirst portion of the heated particles of FesOc and FeS thus producedwith said low A. P. I. gravity hydrocarbon oil to be coked, suspending asecond portion of said particles in heated fiue gas thereby heating saidparticles which are subsequently introduced into said reducingregeneration zone, suspending the remaining portion of particles ofFesO4 and FeS in a gas containing oxygen, introducing this suspensioninto said fiuidized oxidizing regeneration zone thereby effecting theoxidation of said particles to FezOs forming gases containing sulfurdioxide, contacting particles of FezOa thus formed with a gas containingcarbon monoxide produced from said fiuidized reducing zone therebyconverting said FezOs to FesOi and combining the particles of Fe3O4 thusformed with said low A. P. I. gravity hydrocarbon oil to be coked.

9. A process according to claim 8 which comprises a fiuidized cokingzone into which `said desde@ lowl Pi l. gravity hydrocarbon. oilcombined with heated particles of FesOii and FeSl` is. introduced',maintaining a level of suspended cokeladenv particles therein,separating a coker distillate therefrom, separating coke-laden particlesof Fe304 and Fes` therefrom and introducing` the coke-laden particles!thus producedv into said iuidized reducing regeneration zone.

A process according to claim awherein-said loW A+P. I. gravi-tyhydrocarbon oil is cokedY at a temperature between about 700 F. and 1200F., said coke-laden FeaOi is reduced to FeO at a temperature offrom1000D Eto abouti1500-u E'. in the presence of a recycle gas havingav` carbon monoxide to carbon dioxide ratio of atleast 1.0, wherein saidfluidized hydrogen generation zone is operatedv at a temperature of fromabout 800 to above about 1500 F.' and whereiny said fluidized' oxidizingregeneration zone is operated at a temperature between about 1000-D F.and about 2000. F.

11. A process according to claim -wherein said c'oking zone, saidfluidized reducing regeneration zone,l said duidized oxidizingregeneration zone, and said luidized hydrogen generationv zone areoperated at pressures of from about to about 200 pounds per square inchgauge. Y

12. An apparatus for: the production of hydrogen which comprises incombination a hydrogen generation vessel, ay reducing regenerationvessel and an oxidizing regeneration vessel, an outlet conduit for gasesfrom the top of each of said vessels, an outlet conduit for solids fromthe bottom of each of said Vessels', an inlet conduit for fluids'containing suspended solids into each of said vessels, a conduit forrecirculating part of the solids removed from said outlet conduit fromeach of said vessels into the inlet conduit of the same vessel, acoking'vessel, an inletconduit for hydrocarbon' and suspended solidsinto saidl coking f vessel, two conduits for solids, one each from thebottom of said hydrogen generation and oxidizing. regeneration vesselsopening into said inlet conduit into said coking vessel, an outletconduit for a pyrolyzed hydrocarbon from the top of said coking Vessel,an outlet' conduit for solids from said coking vessel opening into theinlet conduit into said reducing regeneration vessel; said outletconduit for solids from the bottom of said reducing regeneration vessel'opening into said inlet conduit for steam into the bottom of saidhydrogen generation vessel and a conduit communicating thevoutletconduit for solids from said hydrogen generation vessel andthe inletconduit into the. bottom of' said oxidizing regeneration vessel.

13- An apparatus for the production of hydrogen which comprises a cokingvessel, a reducing regeneration Vessel, a hydrogen generation Vessel andan oxidizingr regeneration vessel, an inlet conduit' for hotsuspendedsolids anda hydrocarbon to be pyrolyzed opening into said coking vessel,an outlet from the top thereof' for' a pyrolyzed hydrocarbon vapor, anoutlet conduit for coke-laden solids from the bottom thereofcommunicatingA with an inlet conduit for air and suspended coke-ladensolids opening into the bottom of said reducing regeneration vessel, aconduit for recirculated gases communicating the top with the bottomthereof, an outlet conduit for gases from the topthereoan outlet conduitfor solidsfrom the bottom thereof communicating with an inlet conduitfor steam and suspended solids opening into'the bottom of said; hydrogengeneration vessel, a; conduit for recirculated gases communicating thetop' with the bottom thereof; an outlet conduit for gases from the topthereof, an` outlet conduit for solids therefrom communicating with saidinletconduit-for hydrocarbon intosaid coking Vessel and alsocommunieating with an inlet conduit for air and suspended solidsf intothe bottom of said oxidizing regeneration vessel, a conduit forrecirculatedgases communicating the top with the bottom thereof, anoutlet` conduit for gases from the top thereof, an outlet conduit forsolids from the bottom thereof communicating' with` the inlet conduitfor hydrocarbon into saidccking vessel and conduits for recirculatedsolids. communicating the outletconduits for solids from each of' saidreducing regeneration, hydrogen generation and oxidizing regenerationvessels' communicating with said inlet conduits of the same Vessel.

14.l An apparatus according to claim 13 in combination with a conduitfor recirculated vapors communicating the top with the bottom of saidcoking vessel and wherein said inlet conduit for said hydrocarbon and`suspended solids enters the bottom of said coking vessel.

15. An apparatus which comprises a coking vessel, a reducingregeneration Vessel, anoxidizing regeneration vessel and a hydrogengeneration Vessel, said vessels being adapted to contacting enteringgases with iiuidized solid particles, each of saidl reducingregeneration, oxidizing regeneration and hydrogen gener-ation vessels:beingprovided with means for removing solids therefrom by gravity andmeans for recirculating said solids in suspension to the same vessel, aninlet conduit for heated solid particles and a hydrocarbon oilv openinginto said coking vessel, an outlet conduit therefrom for a cokerdistillate, a` conduit therefrom for coke-laden s0lids,.an inlet conduitfor said coke-laden solids from' said coking vessel opening into saidreducing regeneration vessel, conduit and blower means for removing fromthe top thereof and recirculating a carbon monoxide bearing gas into thebottom of said reducing regenerator Vessel, anl outlet conduit forcoke-free reduced particles therefrom communicating with the inletconduit for said reduced particles into said hydrogen generation vessel,an outlet conduit for hydrogen product therefrom, an outletconduit forspent solid particles therefromv communicating with an inlet conduit forone portion of said spent solid` particlesv into said oxidizingregeneration vessel and with an inlet conduit for another portion ofsaid spent solid particles into said coking vessel and a. conduit foroxidized particles communicating said oxidizing regeneration vessel withsaid inlet conduit to said coking vessel.

16. An' apparatus for the production of hydrogen whichcomprises incombination a hydrogen generation vessel, a` reducing regenerationvessel and a hydrocarbon coking vessel, an outlet conduit for gases andvapors from the top of each of said vessels, an outlet conduit forsolids from the'bottom of each oi said vessels, an inlet conduit foriiuids containing suspended solids into each ofv said vessels, a conduitfor recirculating part of the solids removed from said outlet conduitfrom each of said vessels into the inlet conduit of the same vessel,means for introducing a hydrocarbon oil and suspende-d soiids throughsaid inlet conduitv of' said coking Vessel, a ccnduitfor'solidscommunicating the bottom of said hydrogen generation vessel with theinlet conduit into said coking vessel, a conduit for cokeladen solidscommunicating the solids outlet of said coking vessel with said reducingregeneration Vessel, said outlet conduit for solids from the bottom ofsaid reducing regeneration vessel opening into said inlet conduitopening into the bottom of said hydrogen generation vessel.

17. An apparatus for the production of hydrogen which comprises incombination a. hydrogen generation vessel, a reducing regenerationvessel and a hydrocarbon coking means, an outlet conduit for gases andvapors fromthe top of each of said vessels, an outlet conduit for solidsfrom the bottom of each of said Vessels, an inlet conduit for iiuidscontaining suspended solids into each of said vessels, means forintroducing a hydrocarbon oil and suspended solids through the inletconduit for fluids containing suspended solids into said coking means, aconduit for solids communicating the bottom of said hydrogen generationvessel with the inlet Vconduit into said coking means, a conduit forcokeladen solids communicating the solids outlet of said coking meanswith said reducing regeneration vessel, said outlet conduit for solidsfrom HOMER C. REED. CLYDE H. O. BERG.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,273,297 Szayna Feb. 17, 1942 2,296,522 Hartley Sept. 22,1942 2,348,418 Roesch et al. May 9, 1944 2,407,371 Jahnig Sept. 10, 19462,449,635 Barr Sept. 21, 1948 OTHER REFERENCES Taylor: IndustrialHydrogen, 1921, Chemical Catalog Co., Inc., New York, page 52.

1. A PROCESS WHICH COMPRISES COKING A HYDROCARBON OIL IN THE PRESENCE OFFLUIDIZED PARTICLES OF A HIGHER OXIDE OF IRON AT A TEMPERATURE BETWEENABOUT 700* F. AND ABOUT 1200* F. FORMING A COKER DISTILLATE ANDCOKE-LADEN HIGHER IRON OXIDE PARTICLES, SEPARATING SAID COKER DISTILLATEFROM SAID PARTICLES, SUBJECTING SAID COKE-LADEN PARTICLES TO TREATMENTAT A TEMPERATURE BETWEEN ABOUT 1000* F. AND ABOUT 1500* F. WHILE IN AFLUIDIZED STATE IN A GAS CONTAINING OXYGEN TO EFFECT THE COMBUSTION OFSAID COKE THEREFROM AND THE DIRECT HEATING AND THE CARBON REDUCTION OFSAID HIGHER IRON OXIDE FORMING GASES CONTAINING CARBON MONOXIDE ANDCOKE-FREE REDUCED IRON-CONTAINING PARTICLES, FLUIDIZING THE PARTICLESTHUS OBTAINED IN STEAM AT A TEMPERATURE BETWEEN ABOUT 800* F. AND ABOUT1500* F. TO FORM HYDROGEN AND THEREBY REFORMING THE HIGHER IRON OXIDE,SEPARATING HYDROGEN THUS PRODUCED AND RECIRCULATING THE HIGHER IRONOXIDE TO CONTACT FURTHER QUANTITIES OF SAID HYDROCARBON OIL.